FIG. 5 is a diagram showing a conventional cooling apparatus for a starter motor used for a car engine.
In FIG. 5, a reference numeral 1 designates an engine mounted on a car, a numeral 2 designates a cylinder block constituting the engine, a numeral 3 designates a water jacket provided around the cylinder block, a numeral 4 designates an upper hose for feeding a cooling liquid warmed in the water jacket to a radiator 5, a numeral 6 designates a lower hose for feeding the cooling liquid cooled in the radiator 5 to the water jacket 3, and a numeral 7 designates a water pump interposed between the lower hose 6 and the water jacket 3 to apply a pressure to the cooling liquid to thereby forcibly circulate it.
A numeral 108 designates a starter motor for driving the engine and provided with a pinion 108a for driving the ring gear of the engine (not shown). There is a cooling liquid circulating system in which a part of the cooling liquid for cooling the engine is supplied in the yoke of the starter motor, and the cooling liquid is passed through the conduit formed in the yoke to cool the stator core and the field coil, and the cooling liquid is fed into the lower hose 6.
In the conventional apparatus having the construction as above-mentioned, a part of the cooling liquid in the engine 1 is fed from the water jacket 3 surrounding the cylinder block 2 to the cooling liquid conduit in the starter motor 108, and then, the cooling liquid flows in the conduit while the stator core and the field coil of the starter motor 108 are cooled. The cooling liquid is introduced with the lower hose 6 which forms a discharging path from the radiator 5. Since the effect of suction depending on a flow rate of the cooling liquid discharged from the radiator 5 is applied to the cooling liquid flowing through the conduit, there is obtainable good circulating condition for the cooling liquid in the conduit of the starter motor 108; thus, the stator core and the field coil are effectively cooled.
In the above-mentioned conventional cooling apparatus for the starter motor, when there takes place a fault such as breakage of the radiator with the result that the flow rate of the cooling liquid becomes small, cooling of the engine can not be sufficiently performed, whereby the temperature in the engine is increased and the temperature of the cooling liquid is abnormally elevated.
In this case, if a driver of the car doesn't become aware of the fault, the cooling liquid of a high temperature or a hot gas resulted by the evaporation of the warmed cooling liquid is supplied to the cooling liquid conduit in the starter motor 108 by the action of the water pump, whereby there occurs a serious problem of reduction in cooling effect for the stator core and the field coil. In the worst case, they are heated rather than cooled.
There is another problem. Namely, in the winter season, the cooling liquid is supplied to the cooling liquid conduit in the starter motor 108 even when the temperature of the cooling liquid in the engine 1 is abnormally low, whereby the elements to be cooled of the starter motor 108 are excessively cooled.
FIG. 6 is a diagram showing a conventional cooling apparatus for the generator used for a car. The construction as in FIG. 6 is the same as that in FIG. 5, provided that an a.c. generator 208 for a car is communicatively connected between the water jacket 3 and the lower hose 6. Accordingly, description concerning the same parts is omitted.
In the same manner as described with reference to FIG. 5, the cooling liquid is supplied from the water jacket 3 to the generator casing of the a.c. generator; is passed through the cooling liquid conduit in the casing during which the stator core and the stator coil are cooled, and is introduced into the lower hose 6. In the cooling apparatus shown in FIG. 6, there are the same problems as described with reference to FIG. 5, namely, there takes place reduction in the cooling effect due to the fault of the radiator and excessive cooling in the winter season.